In vivo MRI and ex vivo quantification of iron and Kupffer cells demonstrate residual phagocytic activity in mouse liver after a gadolinium chloride injection.

Kupffer cells (KCs), the resident macrophages of the liver, display a phagocytic activity that is not well quantified in animal models. Its experimental invalidation in rodents has been carried out by various means, among which the gadolinium chloride (GdCl₃) injection has been widely used, and has been generally monitored by ex vivo techniques. The aim of our study was to determine the KC phagocytic activity induced in mouse liver following a single GdCl₃ injection, through Magnetic Resonance Imaging (MRI) measurement of liver uptake of Ferumoxide in vivo, and through ex vivo quantification of Perls positive and F4/80 labeled macrophages.

Platelets, thrombospondin-1 and human dermal fibroblasts cooperate for stimulation of endothelial cell tubulogenesis through VEGF and PAI-1 regulation.

During cutaneous wound repair, platelets, dermal fibroblasts (DF) and endothelial cells all cooperate. We have presently investigated the regulation of endothelial cell tubulogenesis by human platelet thrombospondin-1 (TSP-1), in comparison to transforming growth factor-beta1 (TGF-beta1) and total platelet lysates (PL), in a fibrin matrix cell culture system incorporating DF. TSP-1, TGF-beta1 and PL all stimulated VEGF expression in DF dose dependently at mRNA and protein level.

The effect of hormones on bone growth is mediated through mechanical stress.

Mechanical stresses play a key role in regulating cell growth and cell differentiation. Using mechanical and physiological data available in the literature, we are able to construct a growth curve of a child, which we compare to the standard curve. It appears likely that the impact of hormones on pubertal growth rate sprout followed by growth arrest can be solely explained by increased mechanical stresses.

Organization of the cytokeratin network in an epithelial cell.

The cytoskeleton is a dynamic three-dimensional structure mainly located in the cytoplasm. It is involved in many cell functions such as mechanical signal transduction and maintenance of cell integrity. Among the three cytoskeletal components, intermediate filaments (the cytokeratin in epithelial cells) are the best candidates for this mechanical role.

Herpesvirus, cytomegalovirus, human sperm and assisted fertilization.

Background: The effect of viral particles on the motility of human sperm and the relationship between sperm and virus are of importance particularly in assisted fertilization.

Methods: We incubated ejaculated sperm with or without seminal fluid with either herpes simplex virus type 2 (HSV2) or human cytomegalovirus (HCMV). For each experiment, 5 x 10(5) sperm were incubated with a viral load of between 10(4) and 10(6) plaque-forming units.